Datasheet LT1573 (Analog Devices)
| Fabricante | Analog Devices |
| Descripción | Low Dropout PNP Regulator Driver |
| Páginas / Página | 16 / 1 — FEATURES. DESCRIPTIO. Low Cost Solution for High Current, Low Dropout. … |
| Formato / tamaño de archivo | PDF / 183 Kb |
| Idioma del documento | Inglés |
FEATURES. DESCRIPTIO. Low Cost Solution for High Current, Low Dropout. Regulators. Fast Transient Response Needs Much Less
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LT1573 Low Dropout PNP Regulator Driver
U FEATURES DESCRIPTIO
■
Low Cost Solution for High Current, Low Dropout
The LT ®1573 is a regulator driver IC designed to provide
Regulators
a low cost solution for applications requiring high current, ■
Fast Transient Response Needs Much Less
low dropout and fast transient response. When combined
Bulk Capacitance
with an external PNP power transistor, this device pro- ■
Latching Overload Protection Minimizes
vides load current up to 5A with dropout voltages as low
Heat Sink Size
as 0.35V. The LT1573 circuitry is designed for extremely ■
Precision Output Voltage (1%)
fast transient response. This greatly reduces bulk storage ■ Single Supply Operation: VIN = 2.8V to 10V capacitance when the regulator is used in applications ■ Small Surface Mount Package with fast, high current load transients. ■ Capable of Very Low Dropout Voltage (<0.2V) To keep cost and complexity low, the LT1573 uses a new ■ Fixed or Adjustable Outputs time-delayed latching overcurrent protection technique ■ Shutdown that requires no external current sense resistor. Base drive
U
is limited for instantaneous protection, and a time-delayed
APPLICATIO S
latch protects the regulator from continuous short ■ 3.3V to 2.5V Regulators circuits. ■ Microprocessor Power Sources The LT1573 is available as an adjustable regulator with an ■ Post Regulator for Switching Supplies output range of 1.27V to 6.8V and with fixed output ■ High Efficiency Linear Regulators voltages of 2.5V, 2.8V and 3.3V. Output accuracy is better ■ Ultralow Dropout Regulators than 1% to meet the critical regulation requirement of fast ■ Low Voltage Linear Regulators microprocessors. A special 8-pin, fused-lead surface mount package is used to minimize regulator footprint and pro- , LTC and LT are registered trademarks of Linear Technology Corporation. vide adequate heat sinking.
U TYPICAL APPLICATIO
CC 100pF RC
Transient Response for
1k FB COMP
0.2A to 5A Output Load Step
LATCH VOUT LT1573 + CTIME SHDN VIN RD RB 50mV/DIV 24Ω 50Ω QOUT GND DRIVE MOTOROLA D45H11 VIN VOUT 5V 3.3V R1 COUT1 CIN + + C 1.6k OUT2 1µF 100µF 220µF 2.5A/DIV CER LOAD TANT TANT × 24 R2 1k GND 10µs/DIV 1573 F01a VOUT = 1.265V (1 + R1/R2) 1573 F01 FOR T < 45°C, COUT1 = 24 × 1µF Y5V CERAMIC SURFACE MOUNT CAPACITORS. FOR T > 45°C, COUT1 = 24 × 1µF X7R CERAMIC SURFACE MOUNT CAPACITORS. PLACE COUT1 IN THE MICROPROCESSOR SOCKET CAVITY
Figure 1. 3.3V, 5A Microprocessor Supply
sn1573 1573fas 1
U FEATURES DESCRIPTIO
■
Low Cost Solution for High Current, Low Dropout
The LT ®1573 is a regulator driver IC designed to provide
Regulators
a low cost solution for applications requiring high current, ■
Fast Transient Response Needs Much Less
low dropout and fast transient response. When combined
Bulk Capacitance
with an external PNP power transistor, this device pro- ■
Latching Overload Protection Minimizes
vides load current up to 5A with dropout voltages as low
Heat Sink Size
as 0.35V. The LT1573 circuitry is designed for extremely ■
Precision Output Voltage (1%)
fast transient response. This greatly reduces bulk storage ■ Single Supply Operation: VIN = 2.8V to 10V capacitance when the regulator is used in applications ■ Small Surface Mount Package with fast, high current load transients. ■ Capable of Very Low Dropout Voltage (<0.2V) To keep cost and complexity low, the LT1573 uses a new ■ Fixed or Adjustable Outputs time-delayed latching overcurrent protection technique ■ Shutdown that requires no external current sense resistor. Base drive
U
is limited for instantaneous protection, and a time-delayed
APPLICATIO S
latch protects the regulator from continuous short ■ 3.3V to 2.5V Regulators circuits. ■ Microprocessor Power Sources The LT1573 is available as an adjustable regulator with an ■ Post Regulator for Switching Supplies output range of 1.27V to 6.8V and with fixed output ■ High Efficiency Linear Regulators voltages of 2.5V, 2.8V and 3.3V. Output accuracy is better ■ Ultralow Dropout Regulators than 1% to meet the critical regulation requirement of fast ■ Low Voltage Linear Regulators microprocessors. A special 8-pin, fused-lead surface mount package is used to minimize regulator footprint and pro- , LTC and LT are registered trademarks of Linear Technology Corporation. vide adequate heat sinking.
U TYPICAL APPLICATIO
CC 100pF RC
Transient Response for
1k FB COMP
0.2A to 5A Output Load Step
LATCH VOUT LT1573 + CTIME SHDN VIN RD RB 50mV/DIV 24Ω 50Ω QOUT GND DRIVE MOTOROLA D45H11 VIN VOUT 5V 3.3V R1 COUT1 CIN + + C 1.6k OUT2 1µF 100µF 220µF 2.5A/DIV CER LOAD TANT TANT × 24 R2 1k GND 10µs/DIV 1573 F01a VOUT = 1.265V (1 + R1/R2) 1573 F01 FOR T < 45°C, COUT1 = 24 × 1µF Y5V CERAMIC SURFACE MOUNT CAPACITORS. FOR T > 45°C, COUT1 = 24 × 1µF X7R CERAMIC SURFACE MOUNT CAPACITORS. PLACE COUT1 IN THE MICROPROCESSOR SOCKET CAVITY
Figure 1. 3.3V, 5A Microprocessor Supply
sn1573 1573fas 1